This application is co-pending with U.S. patent application Ser. No. 023,161, filed Mar. 6, 1987 for "Method of Making a Long Lived High Current Density Cathode From Tungsten and Iridium Powders" by L. E. Branovich, G. L. Freeman and B. Smith, and now U.S. Pat. No. 4,708,681, assigned to a common assignee. In that application, there is disclosed and claimed a method of making a long lived high current density cathode suitable for operation in microwave devices in which a mixture of tungsten and iridium powders is processed with an activator into a porous billet and the porous billet then impregnated with a chemical mixture of barium oxide, strontium oxide, and aluminum oxide by impregnating the billet in a dry hydrogen furnace at a temperature at which the impregnant melts. This provides the barium atoms that are needed for the generation of electrons.
Though the Ser. No. 023,161 method increases the electron emission of the cathode to a degree, it would be desirable to increase the life and current density of the cathode to an even greater degree.